Compact flash boot speed versus laptop hard disk - should the CF be faster?

[Tawnos]

First, some background:
I'm developing an XP embedded image, using the enhanced write filter to minimize writes to the system disk. Windows prefetching, NTFS last access timestamps, system restore, et cetera, are all turned off per the Microsoft EWF Performance recommendations.

The CF card being used is a Delkin Devices 1GB Industrial CF. It is being compared to a Toshiba 3021GAS Hard disk.

Both drives are partitioned the same, and both have an identical copy of the operating system installed. Specifically, the first partition (C holds the application, operating system, et cetera. The second partition (Z holds application persistent data, windows event logs, etc.

Sisoft Sandra reports the hard disk's filesystem to operate at 22MB/s, where the CF gets 9MB/s. However, during testing, the compact flash booted significantly faster than the hard disk (roughly 25% faster). Do any of you know the technical reason for this, and have documentation to support? I have theories (namely, that boot requires a number of small "random access" reads, which greatly benefit the compact flash's seek time over the hard drive's sustained transfer), but I need to be sure I'm presenting the correct data to management. Does my theory seem correct? Is there anything about sustained read speed that would benefit compact flash over hard disks? Have I missed anything obvious? Write speed to the CF is much slower, but I need to figure out why it's reading more quickly during boot.

Thanks for any help.

 

[mwarps]

First, some background:
I'm developing an XP embedded image, using the enhanced write filter to minimize writes to the system disk. Windows prefetching, NTFS last access timestamps, system restore, et cetera, are all turned off per the Microsoft EWF Performance recommendations.

The CF card being used is a Delkin Devices 1GB Industrial CF. It is being compared to a Toshiba 3021GAS Hard disk.

Both drives are partitioned the same, and both have an identical copy of the operating system installed. Specifically, the first partition (C holds the application, operating system, et cetera. The second partition (Z holds application persistent data, windows event logs, etc.

Sisoft Sandra reports the hard disk's filesystem to operate at 22MB/s, where the CF gets 9MB/s. However, during testing, the compact flash booted significantly faster than the hard disk (roughly 25% faster). Do any of you know the technical reason for this, and have documentation to support? I have theories (namely, that boot requires a number of small "random access" reads, which greatly benefit the compact flash's seek time over the hard drive's sustained transfer), but I need to be sure I'm presenting the correct data to management. Does my theory seem correct? Is there anything about sustained read speed that would benefit compact flash over hard disks? Have I missed anything obvious? Write speed to the CF is much slower, but I need to figure out why it's reading more quickly during boot.

Thanks for any help.

http://techreport.com/reviews/2006q3/supertalent-flashide/index.x?pg=1

Check out that article.

As far as the reason goes, boot is generally a large number of smaller file random accessess, yes. Sequential rate on Flash is pretty abysmal.